Depends on what you want to do with your A&P
Number One Pilot,
To answer your question, pardon me for posting one back at you. What you want to do with your A&P?
I got mine, used it sparingly and later went off to fly and recently furloughed from the majors I have used my A&P actively to do warranty work and was grateful to feed my family for the last couple of years.
I went to a school where some of the guys couldn't speak English well and were very unfamiliar with anything other than the metric system.  Yet they are now accomplished mechanics fixing airplanes worldwide.  In the same class we had guys who had built hot rods before coming to our school but lost interest in aviation within the first few years.
I recently was invited to talk about this subject at career day for a local school and this is what I told the young and eager students.  Consider A&P school as an opportunity to develop a skill-set.  You will be familiar with subjects such as welding, hydraulics, sheet metal, basic electricity, engines etc.  It will not only give you the knowledge base to apply to work on airplanes but you can score points with the wife (in my case) for being that handyman of the house.  But, you may never become wealthy and think of it with a useful shelf life of five or seven years.  Very seldom have I run into guys who think this career is everything they expected it to be but they still do it for one reason or the other
On an another note, I have run into folks who used the A&P license and built on it.  There are guys and gals in Disneyland (Roller Coasters), Oil industry, wind energy development firms etc.  Here is a good link for a better read on what may be out there   
http://answers.yahoo.com/question/index?qid=20090129160516AArWBg7
Okay now to your real question, sorry got off on a tangent, just trying to share everything I know.  You want to know the required aptitude, here is the link for O*NET.ORG for Aircraft Mechanics  
http://online.onetcenter.org/link/summary/49-3011.00
Good luck to you and hope I was of help.
Knowledge
    Mechanical — Knowledge of  machines and tools, including their designs, uses, repair, and  maintenance.   
Design — Knowledge of design  techniques, tools, and principles involved in production of precision  technical plans, blueprints, drawings, and models.   
Customer and Personal Service —  Knowledge of principles and processes for providing customer and  personal services. This includes customer needs assessment, meeting  quality standards for services, and evaluation of customer satisfaction.   
Engineering and Technology —  Knowledge of the practical application of engineering science and  technology. This includes applying principles, techniques, procedures,  and equipment to the design and production of various goods and  services.   
Mathematics — Knowledge of  arithmetic, algebra, geometry, calculus, statistics, and their  applications.   
Physics — Knowledge and  prediction of physical principles, laws, their interrelationships, and  applications to understanding fluid, material, and atmospheric dynamics,  and mechanical, electrical, atomic and sub- atomic structures and  processes.   
Transportation — Knowledge of  principles and methods for moving people or goods by air, rail, sea, or  road, including the relative costs and benefits.   
Law and Government — Knowledge  of laws, legal codes, court procedures, precedents, government  regulations, executive orders, agency rules, and the democratic  political process.   
Administration and Management —  Knowledge of business and management principles involved in strategic  planning, resource allocation, human resources modeling, leadership  technique, production methods, and coordination of people and resources.   
Chemistry — Knowledge of the  chemical composition, structure, and properties of substances and of the  chemical processes and transformations that they undergo. This includes  uses of chemicals and their interactions, danger signs, production  techniques, and disposal methods.   
  
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 Skills
    Reading Comprehension —  Understanding written sentences and paragraphs in work related  documents.   
Repairing — Repairing machines  or systems using the needed tools.   
Troubleshooting — Determining  causes of operating errors and deciding what to do about it.   
Equipment Maintenance —  Performing routine maintenance on equipment and determining when and  what kind of maintenance is needed.   
Complex Problem Solving —  Identifying complex problems and reviewing related information to  develop and evaluate options and implement solutions.   
Equipment Selection —  Determining the kind of tools and equipment needed to do a job.   
Writing — Communicating  effectively in writing as appropriate for the needs of the audience.   
Active Listening — Giving full  attention to what other people are saying, taking time to understand the  points being made, asking questions as appropriate, and not  interrupting at inappropriate times.   
Critical Thinking — Using logic  and reasoning to identify the strengths and weaknesses of alternative  solutions, conclusions or approaches to problems.   
Installation — Installing  equipment, machines, wiring, or programs to meet specifications.   
  
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 Abilities
    Finger Dexterity — The ability  to make precisely coordinated movements of the fingers of one or both  hands to grasp, manipulate, or assemble very small objects.   
Control Precision — The ability  to quickly and repeatedly adjust the controls of a machine or a vehicle  to exact positions.   
Problem Sensitivity — The  ability to tell when something is wrong or is likely to go wrong. It  does not involve solving the problem, only recognizing there is a  problem.   
Manual Dexterity — The ability  to quickly move your hand, your hand together with your arm, or your two  hands to grasp, manipulate, or assemble objects.   
Near Vision — The ability to see  details at close range (within a few feet of the observer).   
Written Comprehension — The  ability to read and understand information and ideas presented in  writing.   
Arm-Hand Steadiness — The  ability to keep your hand and arm steady while moving your arm or while  holding your arm and hand in one position.   
Information Ordering — The  ability to arrange things or actions in a certain order or pattern  according to a specific rule or set of rules (e.g., patterns of numbers,  letters, words, pictures, mathematical operations).   
Deductive Reasoning — The  ability to apply general rules to specific problems to produce answers  that make sense.   
Inductive Reasoning — The  ability to combine pieces of information to form general rules or  conclusions (includes finding a relationship among seemingly unrelated  events).
Wages & Employment Trends
 National
    Median wages (2008) $24.71 hourly, $51,390 annual   Employment (2008) 122,000 employees   Projected growth (2008-2018)  Slower than average (3% to 6%)    Projected job openings (2008-2018) 31,400